Merge pull request #90 from AArnott/fix32

Evaluate real preprocessor symbols

src/CodeGeneration.Roslyn.Tasks/build/CodeGeneration.Roslyn.BuildTime.targets

@@ -4,6 +4,7 @@
   <Target Name="GenerateCodeFromAttributes" DependsOnTargets="ResolveReferences" BeforeTargets="CoreCompile;PrepareResources">
     <ItemGroup>
       <Compile_CodeGenInputs Include="@(Compile)" Condition=" '%(Compile.Generator)' == 'MSBuild:GenerateCodeFromAttributes' " />
+      <DefineConstantsItems Include="$(DefineConstants)" />
     </ItemGroup>
     <PropertyGroup>
       <GenerateCodeFromAttributesToolPathOverride Condition="'$(GenerateCodeFromAttributesToolPathOverride)' == ''">codegen</GenerateCodeFromAttributesToolPathOverride>
@@ -13,6 +14,7 @@
       <_CodeGenToolWarningText>dotnet-codegen: Failed to generate the list of generated files. The tool didn't run succesfully. Please check https://github.com/AArnott/CodeGeneration.Roslyn for usage instructions.</_CodeGenToolWarningText>
       <_CodeGenToolResponseFileLines>
 @(ReferencePath->'-r%0d%0a%(Identity)', '%0d%0a')
+@(DefineConstantsItems->'-d%0d%0a%(Identity)', '%0d%0a')
 @(GeneratorAssemblySearchPaths->'--generatorSearchPath%0d%0a%(Identity)', '%0d%0a')
 --out
 $(IntermediateOutputPath)

src/CodeGeneration.Roslyn.Tests/DocumentTransformTests.cs

@@ -117,18 +117,20 @@ public void IfElseDirective_OnUsings_InactiveUsingAndDirectives_Dropped()
         const string source = @"
 using System;
 using CodeGeneration.Roslyn.Tests.Generators;
-#if SOMETHING
+#if SOMETHING_ACTIVE
 using System.Linq;
-#else
+#elif SOMETHING_INACTIVE
 using System.Diagnostics;
+#else
+using System.Never;
 #endif
 
 [EmptyPartial]
 partial class Empty {}";
         const string generated = @"
 using System;
 using CodeGeneration.Roslyn.Tests.Generators;
-using System.Diagnostics;
+using System.Linq;
 
 partial class Empty
 {

src/CodeGeneration.Roslyn.Tests/Helpers/CompilationTestsBase.cs

@@ -85,6 +85,9 @@ protected static Project CreateProject(params string[] sources)
             .WithProjectCompilationOptions(
                 projectId,
                 new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
+            .WithProjectParseOptions(
+                projectId,
+                new CSharpParseOptions(preprocessorSymbols: new[] { "SOMETHING_ACTIVE" }))
             .AddMetadataReferences(projectId, MetadataReferences);
 
         int count = 0;

src/CodeGeneration.Roslyn.Tool/Program.cs

@@ -12,6 +12,7 @@ static int Main(string[] args)
         {
             IReadOnlyList<string> compile = Array.Empty<string>();
             IReadOnlyList<string> refs = Array.Empty<string>();
+            IReadOnlyList<string> preprocessorSymbols = Array.Empty<string>();
             IReadOnlyList<string> generatorSearchPaths = Array.Empty<string>();
             string generatedCompileItemFile = null;
             string outputDirectory = null;
@@ -21,6 +22,7 @@ static int Main(string[] args)
             {
                 syntax.DefineOption("version", ref version, "Show version of this tool (and exits).");
                 syntax.DefineOptionList("r|reference", ref refs, "Paths to assemblies being referenced");
+                syntax.DefineOptionList("d|define", ref preprocessorSymbols, "Preprocessor symbols");
                 syntax.DefineOptionList("generatorSearchPath", ref generatorSearchPaths, "Paths to folders that may contain generator assemblies");
                 syntax.DefineOption("out", ref outputDirectory, true, "The directory to write generated source files to");
                 syntax.DefineOption("projectDir", ref projectDir, true, "The absolute path of the directory where the project file is located");
@@ -50,6 +52,7 @@ static int Main(string[] args)
                 ProjectDirectory = projectDir,
                 Compile = Sanitize(compile),
                 ReferencePath = Sanitize(refs),
+                PreprocessorSymbols = preprocessorSymbols,
                 GeneratorAssemblySearchPaths = Sanitize(generatorSearchPaths),
                 IntermediateOutputDirectory = outputDirectory,
             };

src/CodeGeneration.Roslyn/CompilationGenerator.cs

@@ -46,6 +46,11 @@ public class CompilationGenerator
         /// </summary>
         public IReadOnlyList<string> ReferencePath { get; set; }
 
+        /// <summary>
+        /// Gets or sets a set of preprocessor symbols to define.
+        /// </summary>
+        public IEnumerable<string> PreprocessorSymbols { get; set; }
+
         /// <summary>
         /// Gets or sets the paths to directories to search for generator assemblies.
         /// </summary>
@@ -309,6 +314,8 @@ private CSharpCompilation CreateCompilation(CancellationToken cancellationToken)
             var compilation = CSharpCompilation.Create("codegen")
                 .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
                 .WithReferences(this.ReferencePath.Select(p => MetadataReference.CreateFromFile(p)));
+            var parseOptions = new CSharpParseOptions(preprocessorSymbols: this.PreprocessorSymbols);
+
             foreach (var sourceFile in this.Compile)
             {
                 using (var stream = File.OpenRead(sourceFile))
@@ -318,8 +325,9 @@ private CSharpCompilation CreateCompilation(CancellationToken cancellationToken)
                     compilation = compilation.AddSyntaxTrees(
                         CSharpSyntaxTree.ParseText(
                             text,
-                            path: sourceFile,
-                            cancellationToken: cancellationToken));
+                            parseOptions,
+                            sourceFile,
+                            cancellationToken));
                 }
             }